Setup and use on mobile devices is generally straightforward, as long as you watch out for a few potential glitches. It should be no surprise that setup with Windows Phone 7 devices is the simplest. Just enter your password and username, and Windows Phone 7 does the rest. You'll then be able to use your mail via Windows Phone 7's Outlook app. However, you may not see older e-mails that have been sent and received. That's because the default setting for Outlook on Windows Phone 7 only syncs mail that has been sent and received in the last three days.

You can change that setting to the last seven days, the last two weeks or the last month, or you can set it up so you can view mail sent and received at any time. In Outlook on Windows Phone 7, get to the settings screen, then select "Sync settings-->Download e-mail from" and make your choice about how you want mail synced.

Setting it up on other phones generally takes a little more work. In Android, for example, you have to go into My Accounts and set up a new Corporate Sync Account. For the Domain/username field, you have to append the address of your Office 365 account to the front of your username. For example, if your Office 365 account is mydomain.onmicrosoft.com, and your username is pgralla, you'd enter mydomain.onmicrosoft.com/pgralla in that field. For the Server field, you enter m.outlook.com. Once you do that, it works and syncs as you would expect.

Even though Exchange 365 is hosted in the cloud, rather than on your company's server, you still get a full suite of administrative tools. You can easily add new Outlook users, either singly or in bulk (via .CSV files), determine whether users get administrative rights, and so on.